Method of forming artificial teeth from gold and plastic



Jan. 25, 1955 s, LEVINE 2,700,184

METHOD OF FORMING ARTIFICIAL TEETH FROM GOLD AND PLASTIC Filed March 25, 1951 m2 mvro HYMAN 5. V/A/E A TTOQNEYS United States Patent() METHOD OF FORMING ARTIFICIAL TEETH FROM GGLD AND PLASTIC Hyman S. Levine, New York, N. Y.

Application March 23, 1951, Serial No. 217,136

1 Claim. (Cl. 18--55.1)

This invention relates to prefabricated tooth blanks made from soft dental wax and to a method for forming an artificial tooth therefrom.

In the design of artificial teeth for either permanent or movable bridge work, the dental technician is obliged at present to prepare a wax blank from which the tooth is in turn cast. The preparation of such blanks 15 both time consuming and tedious while the quality of the finished product usually depends upon the indlvidual skill of the technician. In addition, existing methods may require an excessive amount of raw materlal such as old.

It is an object of the instant invention to produce more perfect artificial teeth for bridge work and the like than is possible under present methods.

A further object is to facilitate the work of dental technicians.

Still another object is to reduce the raw material requirements in the production of artificial teeth for the type of work described.

Other objects of the instant invention will become apparent in the course of the following specification.

In the accomplishment of these objectives, prefabricated tooth blanks are made from soft dental wax for each tooth type of the mouth together with a series for each type within the reasonably to be expected physical variations thereof. With the master impression of the mouth before the technician, the blank constituting the nearest approach to the desired type and size of tooth is selected. The blank having a low melting point, any variations between the prefabricated blank and actual conditions as given by the mouth impression are quickly corrected by adding to or subtracting from the prefabricated blank. In addition to the facility in fitting, the blank is readily adapted for the use of gold in combination with porcelain or the like. Thus, the dental technician is able to produce a more perfect blank in less time than heretofore possible with a substantial saving in raw material and resulting in a more perfect artificial tooth.

The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawings showing by way of example a preferred embodiment of the inventive idea.

In the drawings:

Figure l is a view in perspective of a prefabricated blank of a back tooth and constructed in accordance with the principles of this invention.

Figure 2 is a view in perspective of a blank for a front tooth, the blanks for other tooth types being constructed in a manner similar to those shown in Figures 1 and 2.

Figure 3 is a front elevational view of a selected blank fitted into position and prior to being cast.

Figure 4 is a side elevational view of the casting as made from the blank shown in Figure 3 after the plastic has been added, and on an enlarged scale.

Figure 5 is a sectional view along the line 5-5 of Figure 4.

Figure 6 is a back elevational view of a cast tooth in position.

Figure 7 is a back elevational view of a set of lower front teeth made in accordance with the principles of this invention.

Figure 8 is a sectional Figure 7.

Referring now in greater detail to the drawings in view along the line 8-8 of ice 2 which like reference numerals indicate like parts, reference numeral 10 indicates the prefabricated blank of soft dental wax for one of the back teeth, 11 the blank of soft dental wax for one of the front teeth, and 12 (Figures 4 and 6) a casting in gold of a back artificial tooth made from one of the blanks.

The blanks 10 and 11 of soft dental wax are indicative of the blanks made in sets, each set having at least one form for each of the known types. Since variations may arise between each of the known types, there may be a number of blanks for each type between predetermined physical limitations. Obviously, other material than the soft dental wax having somewhat similar physical characteristics could be used.

In Figure 3 there is illustrated a blank 10 of one of the back teeth which has been fitted between the existing anchors 13 and 14 as given by the master impression 25 of the mouth and from which the sprue 15 (Fig. 1) has been removed and the sides and base of which have been adjusted by removing or adding wax or the like until a substantially perfect fit has been made as shown in Figure 3.

Where the tooth cast from the blank is to be all gold, the only work involved with the blank is concerned with fitting. Where the cast tooth is to be a combination of gold and plastic, those portions of the fitted blank that are to be plastic are also removed and the retention member 117 (Fig. 8) inserted for anchoring the plastic materia Of course, any known means may be used for attachilng the artificial tooth or teeth to the anchors, 13 and In Figure 6, the artificial tooth 12 which has been cast from the blank 10 is shown in position.

In Figure 7 there are shown a number of front artificial teeth 17, 18, 19, and 20 which have been cast in the manner previously described except that different shaped blanks, as shown by Figure 2, are used and the artificial teeth resulting therefrom are held in position by any known method between the anchors 23 and 24. The front of these teeth, as shown in Figure 8, may be a plastic 21 which is attached to the front of the gold back 22 and maintained securely in position with the aid of the retention member 17 attached to the gold back 22 during the casting operation, the retention member 17 having been added after the blank has been fitted into the desired position.

The operation is as follows:

For a gold cusp and gold saddle artificial tooth with an acrylic (plastic) face or synthetic porcelain, the blank of the type required for the position in the mouth im pression is selected and the one of the type that provides the nearest approach in length and width for the space required. If the blank is slightly narrower than the space that is to be filled in, wax is added. If the blank is too wide, the wax is thinned. The saddle area of the mouth impression is then oiled. The wax sprue 15 at the base of the blank is cut off and with a spatula the bottom of the blank is gently heated prior to being placed in position on the ridge of the impression. This operation is repeated until the desired fit is obtained. In case a more perfect saddle adaptation to the ridge is required after the blank has been shaped to the saddle area, a thirty-two gauge sheet of wax may be placed over the ridge and the blank placed thereover and joined thereto while the excess is trimmed and removed from the mouth impression. The inside of the blank at the saddle area is checked to see if the wax is thick enough, and, if not, it is added where needed. The bite and alignment are then checked. If an excessive amount of cusp is carved away for the bite, wax is added on the inside of the cusp for reinforcement purposes. The retention for acrylic (plastic) or synthetic porcelain is then placed on the inside of the blank. A 14 gauge wax sprue can be set in the center of the blank or a loop can be made of 20 or 18 gauge one-half round or round wax shapes to go from mesial to distal or to be set from the cusp to the saddle area.

For a gold cusp with acrylic (plastic) to the tissue, the tooth blank is selected in the manner previously described but the lower section is cut away for acrylic in the saddle area and the retention members are placed in the upper part of the blank. To prevent distortion of the wax form when the saddle area of wax is cut away, the hollow buccal surface may be filled with investment and then the wax cut away as desired.

In the case of a tube tooth with gold reinforcement at the cusp, the operation is as previously described ex cept that if an acrylic cusp is desired with stops to maintain the occlusion, a 14 gauge wax sprue is placed in the center of the blank from cusp to saddle which acts as a support for the gold stop and as the retention for the acrylic. The hollow is then filled with investment and the wax cut away for the type of pontic desired.

For the gold sanitary cusp, the lower section of the selected blank is cut away and the upper part fitted with wax to the desired shape.

In the matter of acrylic pontics, the sprue is cut off from the selected blank and the lower end heated with a spatula prior to being seated on the ridge. The wax is then cut away to receive the bar and the waxing completed.

In the case of wax cusps for onlays, either acrylic or gold, the proper blank is selected and the lower section cut away whereupon the blank is placed in position as desired.

It is apparent that the specific illustrations shown above have been given by way of illustration and not by way of limitation and that the structures above described are subject to other variations and modifications without departing from the scope or intent of the invention and all such variations and modifications are to be included within the scope of the present invention.

What is claimed is:

A method of forming an artificial tooth from gold and a plastic for a replacement comprising the steps of forming a hollow blank of soft dental wax of substantially the form and magnitude of the replacement, conforming the blank to the environment of the replacement, severing the hollow blank into two portions, securing a retention member on one of the severed portions with the free end of the member extending toward the second severed portion, making a mold of the severed portion and retention member, making a casting of gold from the mold, making a second mold of the second severed portion, securing the gold casting to the second mold along the line of severance with the retention member extending into the second mentioned mold, and malliiing a second casting of plastic material in the second mo References Cited in the tile of this patent UNITED STATES PATENTS 613,711 Page et al Nov. 8, 1898 713,330 Murray Nov. 11, 1902 1,335,372 Fredericks Mar. 30, 1920 1,896,123 Schweitzer .1 Feb. 7, 1933 2,011,477 Fischer Aug. 13, 1935 

